The laws of orbital mechanics mean that stars always follow elliptical (stretched circular) orbits under the influence of gravity, so in large groups they form either flattened disc-like spirals or ball-shaped ellipticals. The sharp corners of a rectangle should be impossible, but nevertheless astronomers have found several galaxies with apparently rectangular features. For example, LEDA 074886 in the constellation of Eridanus is a compact, rectangular galaxy embedded in a nearby galaxy cluster. The big question is whether its shape is a long-lived structure or brief coincidence – astronomers who have studied it with the giant Japanese Subaru telescope think the latter is more likely, and that a collision and merger between two could have scattered the outlying stars into their current box-like distribution, triggering a wave of starbirth at the new centre.